Lawnmower safety

Abstract

The invention relates to safety improvements for mowers incorporating a chipper, and/or catcher. In one aspect the invention provides safety improvements that only allow operation of the chipper when the mower is below a predetermined threshold ride height. In another aspect, the mower includes one or more side skirts to prevent body parts from entering the cutting zone under the mower. In a still further aspect, the mower has a rear flap including a sub-flap. The mower is arranged so that the sub flap remains closed when a catcher is installed.

The invention claimed is: 
     
       1. A lawn mower, comprising:
 a deck, forming a platform and having an exit aperture at a rear of the deck, 
 a side wall arranged around at least part of a perimeter of the deck, the deck and the side wall enclosing a cutting space under the deck, 
 a front wheel set and a rear wheel set located at a front and the rear of the deck respectively, 
 a motor attached to an outside top of the platform of the deck, having a drive shaft extending downwards through the deck, a lower part of the drive shaft located substantially at a centre of the cutting space, 
 at least one grass cutting blade, connected to the drive shaft within the cutting space so that the drive shaft causes the at least one grass cutting blade to rotate in a substantially horizontal grass cutting plane, 
 a detachable grass catcher receiving grass cuttings from the exit aperture, 
 a rear flap, connected to and pivoting from a top rear edge of the deck to allow the detachable grass catcher to be attached in use, the rear flap: 
 (i) resting on and acting as a lid for a partly open top of the detachable grass catcher when the grass catcher is attached, and 
 (ii) facing downwards to close the exit aperture at the rear of the deck when the grass catcher is not attached, 
 the rear flap having a sub-flap which can open and close independently of the rear flap, the mower further fitted with a biasing mechanism that is adapted to bias the rear flap and sub-flap towards a closed position, at least when the grass catcher is attached to the mower. 
 
     
     
       2. The lawnmower as claimed in  claim 1  wherein the biasing mechanism includes a wire, and a spring, a first end of the wire connected to the mower, a second end connected to the sub flap, the first end and second end connection points and the dimensions of the wire chosen such that when the flap and sub-flap are raised into a position that the flap and sub-flap would be in with the grass catcher attached, the wire and the spring portion of the wire is in tension. 
     
     
       3. The lawmnower as claimed in  claim 2  wherein the location of the first end and second end connection points and the dimensions of the wire are chosen so that the spring is only just in tension when the flap and sub-flap are raised into the position to that the flap and sub-flap would be in with the grass catcher attached. 
     
     
       4. The lawnmower as claimed in  claim 2  wherein at least the first end of the wire is formed as an eyelet. 
     
     
       5. The lawnmower as claimed in  claim 2  wherein the wire is formed so that that part of the wire is formed as a spring and can move and pivot freely relative to the remainder of the wire when not in tension. 
     
     
       6. The lawnmower as claimed in  claim 5  wherein that part of the wire formed as a spring is uppermost when the grass catcher is connected. 
     
     
       7. A lawn mower with an integral chipper or shredder, comprising:
 a deck, forming a platform and having an exit aperture at a rear of the deck, 
 a side wall arranged around at least part of a perimeter of the deck, the deck and the side wall enclosing a cutting space under the deck, 
 a front wheel set and a rear wheel set located at a front and the rear of the deck respectively, 
 a motor attached to an outside top of the platform of the deck, having a drive shaft extending downwards through the deck, a lower part of the drive shaft located substantially at a centre of the cutting space, 
 at least one grass cutting blade or blades, and at least one chipper blade, connected to the drive shaft within the cutting space so that the drive shaft causes the at least one grass cutting blade to rotate in a substantially horizontal grass cutting plane and the at least one chipper blade to rotate in a substantially horizontal chipping plane, 
 a chipper tube having an upper end and a lower end, the lower end opening into the cutting space above and within a perimeter of a cutting disc formed by rotation of the at least one chipper blade in use, the chipper tube having a lid which is normally closed when the mower is operating, the lid fitted with a cut-off mechanism so that if the lid is opened when the ride height of the mower is above a predetermined threshold ride height, the cut-off mechanism will stop the mower motor. 
 
     
     
       8. The lawnmower as claimed in  claim 7 , wherein the predetermined threshold ride height is the lowest ride height setting. 
     
     
       9. The lawnmower as claimed in  claim 7 , wherein the cut-off mechanism is a wire connected between the chipper tube lid and the mower motor,
 the lawnmower, chipper tube lid, and cut-off wire all dimensioned and adjusted so that the lawnmower motor will run without interruption when the lid is closed, but the wire will be pulled beyond a motor cut-off point and stop the motor when the lid is opened if the mower is adjusted to any point above a predetermined ride height. 
 
     
     
       10. The lawnmower as claimed in  claim 7 , wherein the lawnmower is fitted with a pair of microswitches, a first microswitch connected to the lid of the chipper tube, and arranged to be open when the lid is closed,
 a second microswitch located and arranged such that it is open when the mower is below a predetermined threshold ride height, 
 such that the lawnmower motor will be stopped from running when the lid is opened, and the mower is above said predetermined threshold ride height. 
 
     
     
       11. The lawnmower as claimed in  claim 10 , wherein the motor is stopped by grounding a primary winding of an ignition coil. 
     
     
       12. The lawnmower as claimed in  claim 7 , wherein the lid is spring-loaded and biased towards a closed position, the lid fitted with a catch which operates when the mower is set to a ride height below said predetermined threshold ride height to hold the lid in a fully open position, the mower fitted with a safety mechanism so that if the ride height is adjusted above said predetermined threshold ride height, the catch will disengage and the spring will bias the lid towards the closed position. 
     
     
       13. The lawnmower as claimed in  claim 12  wherein the safety mechanism is a bowden wire connected between the chipper tube lid and the lawnmower, the lawnmower, chipper tube lid, catch and bowden wire all dimensioned and adjusted so that when the mower is below said predetermined threshold ride height position, the catch can engage the lid to hold the lid open, and if the mower is adjusted above said predetermined threshold ride height position, the bowden wire will be pulled beyond a cut-off point to disengage the catch and the spring will bias the lid towards the closed position. 
     
     
       14. The lawnmower as claimed in  claim 7 , wherein the lawnmower further has a rear flap, connected to and pivoting from a top rear edge of the deck to allow the detachable grass catcher to be attached in use, the rear flap:
 (i) resting on and acting as a lid for a partly open top of the detachable grass catcher when the grass catcher is attached, and 
 (ii) facing downwards to close the exit aperture at the rear of the deck when the grass catcher is not attached, 
 the rear flap having a sub-flap which can open and close independently of the rear flap, the mower further fitted with a safety clip, adapted so that at least the sub-flap cannot be raised any higher than a normal operating position that the flap and sub-flap would be in when a grass catcher were attached. 
 
     
     
       15. The lawnmower as claimed in  claim 7  wherein the lawnmower further has a rear flap, connected to and pivoting from a top rear edge of the deck to allow the detachable grass catcher to be attached in use, the rear flap:
 (i) resting on and acting as a lid for a partly open top of the detachable grass catcher when the grass catcher is attached, and 
 (ii) facing downwards to close the exit aperture at the rear of the deck when the grass catcher is not attached, 
 
       the rear flap having a sub-flap which can open and close independently of the rear flap, the mower further fitted with a biasing mechanism that is adapted to bias the flap and sub-flap towards a closed position at least when a grass catcher is attached to the mower. 
     
     
       16. The lawnmower as claimed in  claim 15  wherein the biasing mechanism includes a wire, and a spring, a first end of the wire connected to the mower, a second end connected to the sub flap, the first end and second end connection points and the dimensions of the wire chosen such that when the flap and sub-flap are raised into a position that the flap and sub-flap would be in with the grass catcher attached, the wire and in particular the spring portion of the wire is in tension. 
     
     
       17. The lawnmower as claimed in  claim 16  wherein the location of the first end and second end connection points and the dimensions of the wire are chosen so that the spring is only just in tension when the flap and sub-flap are raised into the position that the flap and sub-flap would be in with the grass catcher attached. 
     
     
       18. The lawnmower as claimed in  claim 17  wherein at least the first end of the wire is formed as an eyelet. 
     
     
       19. The lawnmower as claimed in  claim 16  wherein the wire is formed so that that part of the wire is formed as a spring and can move and pivot freely relative to the remainder of the wire when not in tension. 
     
     
       20. The lawnmower as claimed in  claim 16  wherein that part of the wire formed as a spring is uppermost when the grass catcher is connected.